Income and Other Taxes (Credit Carryforwards and Valuation Allowances and Reserves) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Valuation Allowances and Reserves (Details) [Roll Forward]
Reduction of the valuation allowance as a result of the reduction in the UK statutory income tax rate		$ 44				$ 67
Permanently reinvested cumulative undistributed foreign earnings		4,600		$ 3,700
Valuation Allowance Of Deferred Tax Assets [Member]
Valuation Allowances and Reserves (Details) [Roll Forward]
Balance at beginning of period		622		585		632
Additions charged to income		24		57		25
Additions charged to other accounts		77	[1]	6		0
Deductions		61	[2]	26		72	[2]
Balance at end of period		662		622		585
Investment Tax Credit [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 125
Investment Tax Credit [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Expiration		Dec. 31, 2025
Investment Tax Credit [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Expiration		Dec. 31, 2028
Alternative Minimum Tax Credit [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 40
Other [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount	[3]	29
Credit carryforward valuation allowance on other		$ 12
Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Expiration		Dec. 31, 2016
Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Expiration		Dec. 31, 2035
Other [Member] | State [Member]
Credit carryforwards
Credit carryforwards, amount		$ 5
Expiration		Dec. 31, 2022
LG And E And KU Energy LLC [Member] | Valuation Allowance Of Deferred Tax Assets [Member]
Valuation Allowances and Reserves (Details) [Roll Forward]
Balance at beginning of period		$ 0		4		5
Additions charged to other accounts		12	[4]	0		0
Deductions		0		4	[5]	1	[5]
Balance at end of period		12		$ 0		$ 4
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 125
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Expiration		Dec. 31, 2025
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Expiration		Dec. 31, 2028
LG And E And KU Energy LLC [Member] | Alternative Minimum Tax Credit [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 28
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 27
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Expiration		Dec. 31, 2016
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Expiration		Dec. 31, 2035
LG And E And KU Energy LLC [Member] | Other [Member] | State [Member]
Credit carryforwards
Credit carryforwards, amount		$ 5
Expiration		Dec. 31, 2022
Louisville Gas And Electric Co [Member] | Federal [Member]
Credit carryforwards
Credit carryforwards, amount		$ 1
Louisville Gas And Electric Co [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Expiration		Dec. 31, 2031
Louisville Gas And Electric Co [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Expiration		Dec. 31, 2035
Louisville Gas And Electric Co [Member] | State [Member]
Credit carryforwards
Credit carryforwards, amount		$ 2
Expiration		Dec. 31, 2022
Kentucky Utilities Co [Member] | State [Member]
Credit carryforwards
Credit carryforwards, amount		$ 2
Expiration		Dec. 31, 2022

[1] Valuation allowance related to deferred tax assets previously reflected on the PPL Energy Supply Segment. The deferred tax assets and related valuation allowance remain with PP L after the spinoff.

[2] The reductions of the U.K. statutory income tax rates in 2015 and 2013 resulted in $44 million and $67 million in reductions in deferred tax assets and the corresponding valuation allowances. See "Reconciliation of Income Tax Expense" below for more information on the impact of the U.K. Finance Acts 2015 and 2013.

[3] A valuation allowance of $ 12 million has been recorded against the deferred tax assets for these credits .

[4] Represents tax credits expiring in 2016 through 2020 that are more likely than not to expire before being utilized.

[5] Primarily related to the expiration of state capital loss carryforwards .